scholarly journals ICONGETM v1.0 – Flexible two-way coupling via exchange grids between the unstructured-grid atmospheric model ICON and the structured-grid coastal ocean model GETM

2020 ◽  
Author(s):  
Tobias Peter Bauer ◽  
Knut Klingbeil ◽  
Peter Holtermann ◽  
Bernd Heinold ◽  
Hagen Radtke ◽  
...  
Keyword(s):  
Data Exchange ◽  
Coastal Upwelling ◽  
Atmospheric Model ◽  
Ocean Model ◽  
Coupled Models ◽  
Structured Grid ◽  
Process Understanding ◽  
Regional Ocean Model ◽  
Coastal Ocean Model

Abstract. Coupled atmosphere-ocean models are developed for process understanding at the air-sea interface. Over the last 20 years, there have been studies involving simulations in the range of sub-annual simulations to climate scenarios. The development of coupled models highly depends on the kind and quality of the required data exchange between the model interfaces. This work achieved the development of a two-way coupled atmosphere-ocean model ICONGETM with flexible data exchange via exchange grids provided by the widely used ESMF regridding package. The regridding of flux data between the unstructured atmosphere model ICON and the structured regional ocean model GETM is conducted via these exchange grids. The newly developed model ICONGETM has been demonstrated for a coastal upwelling scenario in the Central Baltic Sea.

scholarly journals ICONGETM v1.0 – flexible NUOPC-driven two-way coupling via ESMF exchange grids between the unstructured-grid atmosphere model ICON and the structured-grid coastal ocean model GETM

2021 ◽  
Vol 14 (8) ◽  
pp. 4843-4863
Author(s):  
Tobias Peter Bauer ◽  
Peter Holtermann ◽  
Bernd Heinold ◽  
Hagen Radtke ◽  
Oswald Knoth ◽  
...  
Keyword(s):  
Data Exchange ◽  
Coastal Upwelling ◽  
Weather Prediction ◽  
Coupled Model ◽  
Coastal Ocean ◽  
Ocean Model ◽  
Model System ◽  
Ocean Dynamics ◽  
Atmosphere Model ◽  
Coastal Ocean Model

Abstract. Two-way model coupling is important for representing the mutual interactions and feedbacks between atmosphere and ocean dynamics. This work presents the development of the two-way coupled model system ICONGETM, consisting of the atmosphere model ICON and the ocean model GETM. ICONGETM is built on the latest NUOPC coupling software with flexible data exchange and conservative interpolation via ESMF exchange grids. With ICON providing a state-of-the-art kernel for numerical weather prediction on an unstructured mesh and GETM being an established coastal ocean model, ICONGETM is especially suited for high-resolution studies. For demonstration purposes the newly developed model system has been applied to a coastal upwelling scenario in the central Baltic Sea.

scholarly journals The effect of coastal upwelling on the sea-breeze circulation at Cabo Frio, Brazil: a numerical experiment

1998 ◽  
Vol 16 (7) ◽  
pp. 866-871 ◽  
Author(s):  
S. H. Franchito ◽  
V. B. Rao ◽  
J. L. Stech ◽  
J. A. Lorenzzetti
Keyword(s):  
Coastal Upwelling ◽  
Surface Wind ◽  
Three Dimensional ◽  
Sea Breeze ◽  
Atmospheric Model ◽  
Ocean Model ◽  
Breeze Circulation ◽  
Mesoscale Meteorology ◽  
Forcing Function ◽  
Cabo Frio

Abstract. The effect of coastal upwelling on sea-breeze circulation in Cabo Frio (Brazil) and the feedback of sea-breeze on the upwelling signal in this region are investigated. In order to study the effect of coastal upwelling on sea-breeze a non-linear, three-dimensional, primitive equation atmospheric model is employed. The model considers only dry air and employs boundary layer formulation. The surface temperature is determined by a forcing function applied to the Earth's surface. In order to investigate the seasonal variations of the circulation, numerical experiments considering three-month means are conducted: January-February-March (JFM), April-May-June (AMJ), July-August-September (JAS) and October-November-December (OND). The model results show that the sea-breeze is most intense near the coast at all the seasons. The sea-breeze is stronger in OND and JFM, when the upwelling occurs, and weaker in AMJ and JAS, when there is no upwelling. Numerical simulations also show that when the upwelling occurs the sea-breeze develops and attains maximum intensity earlier than when it does not occur. Observations show a similar behavior. In order to verify the effect of the sea-breeze surface wind on the upwelling, a two-layer finite element ocean model is also implemented. The results of simulations using this model, forced by the wind generated in the sea-breeze model, show that the sea-breeze effectively enhances the upwelling signal.Key words. Meteorology and atmospheric dynamics (mesoscale meteorology; ocean-atmosphere interactions) · Oceanography (numerical modeling)

scholarly journals The co-influence of the sea breeze and the coastal upwelling at Cabo Frio: a numerical investigation using coupled models

2011 ◽  
Vol 59 (2) ◽  
pp. 131-144 ◽  
Author(s):  
Flávia Noronha Dutra Ribeiro ◽  
Jacyra Soares ◽  
Amauri Pereira de Oliveira
Keyword(s):  
Positive Feedback ◽  
Coastal Upwelling ◽  
Coupled Model ◽  
Sea Breeze ◽  
Atmospheric Model ◽  
Breeze Circulation ◽  
Coupled Models ◽  
Initial Field ◽  
Oceanic Model ◽  
Cabo Frio

A coupled atmospheric-oceanic model was used to investigate whether there is a positive feedback between the coastal upwelling and the sea breeze at Cabo Frio - RJ (Brazil). Two experiments were performed to ascertain the influence of the sea breeze on the coastal upwelling: the first one used the coupled model forced with synoptic NE winds of 8 m s-1 and the sign of the sea breeze circulation was set by the atmospheric model; the second experiment used only the oceanic model with constant 8 m s-1 NE winds. Then, to study the influence of the coastal upwelling on the sea breeze, two more experiments were performed: one using a coastal upwelling representative SST initial field and the other one using a constant and homogeneous SST field of 26°C. Finally, two more experiments were conducted to verify the influence of the topography and the spatial distribution of the sea surface temperature on the previous results. The results showed that the sea breeze can intensify the coastal upwelling, but the coastal upwelling does not intensify the sea breeze circulation, suggesting that there is no positive feedback between these two phenomena at Cabo Frio.

scholarly journals Mesoscale ocean fronts enhance carbon export due to gravitational sinking and subduction

2017 ◽  
Vol 114 (6) ◽  
pp. 1252-1257 ◽  
Author(s):  
Michael R. Stukel ◽  
Lihini I. Aluwihare ◽  
Katherine A. Barbeau ◽  
Alexander M. Chekalyuk ◽  
Ralf Goericke ◽  
...  
Keyword(s):  
Coastal Upwelling ◽  
Sediment Traps ◽  
Ocean Model ◽  
Model Fit ◽  
New Production ◽  
Carbon Export ◽  
Ocean Fronts ◽  
Regional Ocean Model ◽  
Particle Export

Enhanced vertical carbon transport (gravitational sinking and subduction) at mesoscale ocean fronts may explain the demonstrated imbalance of new production and sinking particle export in coastal upwelling ecosystems. Based on flux assessments from 238U:234Th disequilibrium and sediment traps, we found 2 to 3 times higher rates of gravitational particle export near a deep-water front (305 mg C⋅m−2⋅d−1) compared with adjacent water or to mean (nonfrontal) regional conditions. Elevated particle flux at the front was mechanistically linked to Fe-stressed diatoms and high mesozooplankton fecal pellet production. Using a data assimilative regional ocean model fit to measured conditions, we estimate that an additional ∼225 mg C⋅m−2⋅d−1 was exported as subduction of particle-rich water at the front, highlighting a transport mechanism that is not captured by sediment traps and is poorly quantified by most models and in situ measurements. Mesoscale fronts may be responsible for over a quarter of total organic carbon sequestration in the California Current and other coastal upwelling ecosystems.

scholarly journals Impact of Assimilating Surface Velocity Observations on the Model Sea Surface Height Using the NCOM-4DVAR*

2016 ◽  
Vol 144 (3) ◽  
pp. 1051-1068 ◽  
Author(s):  
Matthew J. Carrier ◽  
Hans E. Ngodock ◽  
Philip Muscarella ◽  
Scott Smith
Keyword(s):  
Sea Surface Height ◽  
Ocean Model ◽  
Sea Surface ◽  
Surface Velocity ◽  
Velocity Measurements ◽  
Substantial Impact ◽  
Assimilation Experiment ◽  
Regional Ocean Model ◽  
Coastal Ocean Model ◽  
Along Track

Abstract The assimilation of surface velocity observations and their impact on the model sea surface height (SSH) is examined using an operational regional ocean model and its four-dimensional variational data assimilation (4DVAR) analysis component. In this work, drifter-derived surface velocity observations are assimilated into the Navy’s Coastal Ocean Model (NCOM) 4DVAR in weak-constraint mode for a Gulf of Mexico (GoM) experiment during August–September 2012. During this period the model is trained by assimilating surface velocity observations (in a series of 96-h assimilation windows), which is followed by a 30-day forecast through the month of October 2012. A free-run model and a model that assimilates along-track SSH observations are also run as baseline experiments to which the other experiments are compared. It is shown here that the assimilation of surface velocity measurements has a substantial impact on improving the model representation of the forecast SSH on par with the experiment that assimilates along-track SSH observations directly. Finally, an assimilation experiment is done where both along-track SSH and velocity observations are utilized in an attempt to determine if the observation types are redundant or complementary. It is found that the combination of observations provides the best SSH forecast, in terms of the fit to observations, when compared to the previous experiments.

scholarly journals Impact of Ocean–Atmosphere Current Feedback on Ocean Mesoscale Activity: Regional Variations and Sensitivity to Model Resolution

2020 ◽  
Vol 33 (7) ◽  
pp. 2585-2602 ◽  
Author(s):  
Swen Jullien ◽  
Sébastien Masson ◽  
Véra Oerder ◽  
Guillaume Samson ◽  
François Colas ◽  
...  
Keyword(s):  
General Circulation ◽  
Surface Wind ◽  
General Circulation Models ◽  
Atmospheric Model ◽  
Ocean Model ◽  
Model Resolution ◽  
Coupled Models ◽  
Current Feedback ◽  
Regional Variations ◽  
Ocean Atmosphere

AbstractOcean mesoscale eddies are characterized by rotating-like and meandering currents that imprint the low-level atmosphere. Such a current feedback (CFB) has been shown to induce a sink of energy from the ocean to the atmosphere, and consequently to damp the eddy kinetic energy (EKE), with an apparent regional disparity. In a context of increasing model resolution, the importance of this feedback and its dependence on oceanic and atmospheric model resolution arise. Using a hierarchy of quasi-global coupled models with spatial resolutions varying from 1/4° to 1/12°, the present study shows that the CFB induces a negative wind work at scales ranging from 100 to 1000 km, and a subsequent damping of the mesoscale activity by ~30% on average, independently of the model resolution. Regional variations of this damping range from ~20% in very rich eddying regions to ~40% in poor eddying regions. This regional modulation is associated with a different balance between the sink of energy by eddy wind work and the source of EKE by ocean intrinsic instabilities. The efficiency of the CFB is also shown to be a function of the surface wind magnitude: the larger the wind, the larger the sink of energy. The CFB impact is thus related to both wind and EKE. Its correct representation requires both an ocean model that resolves the mesoscale field adequately and an atmospheric model resolution that matches the ocean effective resolution and allows a realistic representation of wind patterns. These results are crucial for including adequately mesoscale ocean–atmosphere interactions in coupled general circulation models and have strong implications in climate research.

scholarly journals Coastal Upwelling Limitation by Onshore Geostrophic Flow in the Gulf of Guinea Around the Niger River Plume

2021 ◽  
Vol 7 ◽  
Author(s):  
Gaël Alory ◽  
Casimir Yélognissè Da-Allada ◽  
Sandrine Djakouré ◽  
Isabelle Dadou ◽  
Julien Jouanno ◽  
...  
Keyword(s):  
Coastal Upwelling ◽  
Ocean Model ◽  
River Plume ◽  
Gulf Of Guinea ◽  
Sea Level Changes ◽  
Current Increase ◽  
Geostrophic Flow ◽  
Regional Ocean Model ◽  
Niger River ◽  
Induced Changes

Wind-driven coastal upwelling can be compensated by onshore geostrophic flow, and river plumes are associated with such flow. We investigate possible limitation of the northeast Gulf of Guinea upwelling by the Niger River plume, using regional ocean model simulations with or without river and dynamical upwelling indices. Here, the upwelling is weakened by 50% due to an onshore geostrophic flow equally controlled by alongshore thermosteric and halosteric sea-level changes. The river contributes to only 20% of this flow, as its plume is shallow while upwelling affects coastal temperature and salinity over a larger depth. Moreover, the river-induced mixed-layer thinning compensates the current increase, with no net effect on upwelling. The geostrophic compensation is due to an abrupt change in coastline orientation that creates the upwelling cross-shore front. The river nonetheless warms the upwelling tongue by 1°C, probably due to induced changes in horizontal advection and/or stratification.

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